/Engine/Source/Editor/Kismet/Public/BlueprintActionMenuBuilder.h
Some action menus require multiple sections. One option is to create multiple FBlueprintActionMenuBuilders and append them together, but that can be unperformant (each builder will run through the entire database separately)... This method provides an alternative, where you can specify a separate filter/heading/ordering for a sub-section of the menu.
void AddMenuSection ( [FBlueprintActionFilter](API\Editor\BlueprintGraph\FBlueprintActionFilter) const & Filter, [FText](API\Runtime\Core\Internationalization\FText) const & Heading, int32 MenuOrder, uint32 const Flags )